Proceedings
of the
BIOLOGY AND MANAGEMENT
OF
TRUE FIR
IN THE
PACIFIC NORTHWEST
SYMPOSIUM
Edited by
Chadwick Dearing Oliver
and
Reid M. Kenady
University of Washington
College of Forest Resources
Seattle, Washington
Institute of Forest Resources
Contribution Number 45
U.S.D.A. Forest Service
Pacific Northwest
Forest and Range Experiment Station
Portland, Oregon
PATTERNS OF HEIGHT GROWTH IN
WESTERN TRUE FIRS
Constance A. Harrington and Marshall D. Murray
ABSTRACT
Height growth of true firs in western North America can be charac­
terized by:
(1)
an initial period of slow juFenile growth,
2)
sites with high Douglas-fir site indexes, but generally ha\'e slower ju­
a fairly
Fenile growth than Douglas:fir. On poor sites, noble .fir can outgrow
3) an extended period of slower but
Douglas-fir in height, primarily because Douglas:fir slows down in
.
Data from young-growth stands in western Washington were used
on its growth relatil'e to Douglas-fir, the authors conclude noble fir
long period of rapid growth, and
still appreciable growth.
height growth more quickly on poor sites than does noble fir·. Based
to assess height growth of noble fir, Pacific silver fir, and grand fir
warrants greater management consideration. Pacific silver fir and
relative to height growth of Douglas-fir as predicted by Douglas-fir
grand fir also warrant more consideration, particularly as compo­
site index. All three true firs are capable of excellent height growth on
nents of mixed stands.
INTRODUCTION
The true firs (Abies spp.) in western North America can eas­
ily be recognized by their distinctive silhouettes. In addition to
their common appearance, they also share similar patterns of
height growth. We first discuss the different phases of height
growth during the lives of true firs and the seasonal progression
of height growth. We next present field data from young­
growth stands of noble fir (A. procera Rehd. ), Pacific silver fir
(A. amabilis [Doug!.] Forbes), and grand fir (A. grandis
[Doug!.] Lind!.) which illustrate some specific patterns of
height growth and the potential for height growth in these spe­
cies. The relationships between height growth of these true firs
and predicted height growth of Douglas-fir (Pseudotsuga men­
ziesii [Mirb.] Franco) are examined and the management im­
plications discussed.
GENERAL PATTERNS OF HEIGHT GROWTH
Graphic representation of true fir height growth shows a
characteristic S-shaped curve which can be divided into three
phases: juvenile or early age; sapling to maturity; and mature
to overmature old age. The length of time a tree is in each
phase varies with species, site, and stand conditions.
During the first or juvenile phase, height growth is charac­
teristically slow. In natural stands, it is not uncommon for
many of the true firs to take up to 20 years to reach breast
height (table 1). Under favorable conditions, however, Pacific
silver, grand, and noble firs are capable of reaching breast
height in five to nine years. Although most of the western true
firs are fairly shade tolerant, in stands of mixed species their
early height growth can be retarded by shade from those with
greater juvenile height growth. Regeneration in uneven-aged
stands can be severely suppressed; Williams (1968b) measured
Pacific silver fir that took over 80 years to reach breast height.
Delays in growing out of the juvenile phase are still evident
many years later. Although most true firs can recover from
early suppression or checks in height growth and show excel­
lent subsequent height growth, they characteristically remain
shorter than trees of the same age that emerged from the juve­
nile phase more rapidly.
Table I. Years to breast height for western true firs under conditions
favorable for regeneration.
Species
Pacific silver fir
White fir
Grand fir
Subalpine fir
California red fir
Noble fir
Years to breast height*
7-20
15-25
5-20
20-40
10-25
5-12
* Sources include Fowells (1965), Hanzlik ( 1925), Stage ( 1959), Williams
( 1968b), and personal field observations.
Height Growth Patterns
In the second major phase, from the sapling stage to matu­
rity, height growth is rapid, generally following a more-or-less
linear trend. The linear portion of the height-growth curve is
most extended on the best sites (Cochran 1979; Herman et al.
1978; Schumacher 1926, 1928; Stage 1959). This period of
rapid height growth is longer for the true firs than for many of
their associates. thus. during this second phase the true firs of­
ten catch up with or surpass associated tree species (Herman
1967).
Height growth slows as trees enter the third, mature to over­
mature, old-age phase of height growth. The true firs are fairly
long-lived, however; on favorable sites, trees 100 to 400 years
old continue to increase appreciably in height. In many old­
growth stands, the true firs are found in dominant or super­
dominant positions. On good sites, most of the western Abies
attain heights of 40 to 60 m. with maximum heights of Pacific
silver, grand, and noble firs ranging from 75 to 85 m (table 2).
True fir height growth is limited to a rather brief period dur­
ing the growing season (figure 1 ) . This is generally true of spe­
cies with determinate height growth and is in contrast to spe­
cies lacking large overwintering terminal buds, such as
hemlock or cedar, which continue to grow in height as long as
conditions are favorable during the growing season. The west­
ern true firs, however, tend to have more rapid terminal expan­
sion than any of their associates, with the possible exception of
Douglas-fir (Fowells 1941; Williams 1968a).
Study locations
• Noble fir
0 Pacific silver fir
• Grand fir
Olympia
•
go
.
,,..
MI. Rainier
.
•
•
•o
eo
0
;o
MI. St. Helens
.. •:
Figure 2. Location of true fir stands studied in western Washington.
100
:F:
90
0,
E
80
.2' 70
.,
,t;;
:
::::
.. 60
c:
50
I
0..
/ /,.
/
I.'
II
t' lj
40
/
.·' ,.I /
:
•
.'
i ,'i / /
! if l/
0
'E 30
¬.,
·
I If
20
.
,'
,.
"
. Āā""·
.... ÿ/ Ă ·.:· "'.·".;,
// / I/
,• ' 1 I
.. /I / :
. ,' ,/,I/
, ..'
.
/
I
I
I
I
I
/
/
//
-- Douglas·llr
- - -Western redcedar
-" - •·- western hemlock
••• • • • • • • • • Lodgepole pine
.. - - - -- Pacdlc s1lver hr
-·-·-·-Nobleflr
-- ••--" Subalpme fir
;'''p''
t.'
.',' ..
10
'/
10
20
May
Figure 1. Seasonal height growth of several northwestern conifers
(Government Camp, Oregon, 1200 m [3900 ft] adapted from Wil­
liams 1968).
COLLECTION AND ANALYSIS OF FIELD
DATA
We collected height and age or annual height growth infor­
mation in 49 true fir stands in western Washington (figure 2) .
Most of the stands were mixed species with Douglas-fir and
210
western hemlock (Tsuga heterophylla [Raf.] Sarg. ) the most
common tree associates. Elevations ranged from 30 to 1300 m
with most of the stands occurring between 600 and 1000 m.
For each site, we determined aspect, elevation, soil series, and
Douglas-fir site index. Elevation and soil series were deter­
mined from topographic and soil maps.Douglas-fir site index
was determine'd using King (1966); 10 or more site trees were
measured for height and age in the younger stands; at least five
site trees were measured in the older stands. If not enough suit­
able Douglas-fir trees were on the site to make an accurate site
index determination, we used the Douglas-fir site index for the
appropriate soil series;' we used soil series to determine the
Douglas-fir site index for about one-fifth of the sites.
On all sites, we determined total height and breast-height
age of the true firs. Some sites had more than one age class
present; we used an average of three trees per species to deter­
mine an average height for each site and age class.
We also determined annual height growth of 17 true fir trees
that came from I 0 different stands. The trees were felled, aged
at breast height, and the distances between branch whorls mea­
sured. The number of rings at breast height for each tree was
verified to equal the number of whorls above breast height.
I. Based on Weyerhaeuser Company soil maps for their Washington tree
farms.
Harrington and Murray
Table 2. Average and maximum heights of mature true firs on good sites
(adapted from Fowells (1965).
120
Tala/ height (Meters)
A1•erage
Maximum
40-60
75
40-55
40-60
61
76
Subalpine fir
18-30
California red fir
Noble fir
40-50
41
57
40-60
83+
Species
Pacific silver fir
White fir
Grand fir
130
39
33
110
' ' ( ( Notif''
100
-rx.uq'“' ''''"'"ll19E.{''
50
40
12
30
t Information from Jerry F. Franklin, Forestry Sciences Laboratory. Cor­
vallis, Oregon.
20
0 0
10
0
3Ž45.61-1 7183-1
79 1 2;.<23-=25 -=27=29>31?33@35'
95:17,
Breasl·helght age (years)
When the trees were young enough to allow accurate determi­
nation, measurements were also made of interwhorl distances Figure 3a. Height growth of two noble firs compared with average
height growth of Douglas-fir on Douglas-fir site index 40 m (130 ft)
below breast height. We avoided any trees of lower crown
(King 1966).
class or with obvious signs of past top damage,
Cumulative height growth was plotted over age for each of
the trees with annual height growth measurements. The height
130
39
growth patterns of the true firs on each site were compared
120
36
with the expected height growth for Douglas-fir on that site, as
0 Q00
110
33
--DO<Jglash•!Kmg19661
100
predicted by Douglas-fir site index (King 1966).
30
90
27
We wished to compare the relative heights of the true firs
"8
I
80 [
with those of Douglas-fir on sites of varying Douglas-fir site in­ :E 24
0
.!1' 2 1
70 þ.
dex. Thus, for each age for which we had data, we regressed
;?;
60
72 1B
height of the true fir against Douglas-fir site index. The regres­ {!.
a
15
50
sion equations were computed individually for noble and Pa­
12 P
40
cific silver firs; grand fir data were insufficient for this analysis.
30
Data from the sites with annual height growth measurements
:
20
?
were included in the regression analyses of each age for which
10
other data were available. The majority of the values used in
L--LAB37-C,D.
,
E
F
G
5
.H
J
.
7
I
9
-,K
3
3
3
5
L
5
1 2
1
2 =27M2 9N31 33O ' °
11 1
the regression analyses, however, were independent for each
Breast·helght age (years)
age.
Douglas-fir site index incorporates the effects of many site Figure 3b. Height growth of three grand fir trees compared with aver­
factors on height growth of Douglas-fir. The effects of some of age height growth of Douglas-fir on Douglasfir site index 40 m (130
these site factors may be species-specific. To evaluate how ft) (King 1966).
well Douglas-fir site index incorporates the effects of aspect
and elevation on true fir height growth, the true fir heights pre­
covery from top damage can be seen (figure 3b) . All three spe­
dicted by the regression equations were compared to actual
cies had excellent growth rates on areas with high Douglas-fir
heights. Sites having heights that deviated from the predicted
site indexes; maximum annual height growth ranged from I . 0
values by more than 10 percent (plus or minus) were tallied by
t o 1. 2 meters (tabie 3). On the better sites. most trees entered
aspect and elevation for each species.
the linear phase of height growth at or just before reaching
breast height; on the poorer sites, however. trees did not begin
rapid height growth until three or four years after passing
RESULTS
breast height. Once trees began rapid height growth, their
The plotted height-growth data illustrated the general trends growth rate was linear for as many years as we had data.
The regressions of true fir height against Douglas-fir site in­
of height growth during the juvenile phase and the early por­
tion of the sapling-to-maturity phase. Delays in entering the dex had correlation coefficients ranging from 0.85 to 0. 98 (all
period of rapid height growth are still evident in reduced height significant at a= .01). All the regression lines (figures 4a and
at later ages (figure 3a). Both minor top damage and rapid re­ b) had positive slopes, indicating greater heights were associ­
0000
GraM f"
'
’
.1:::
""
' 0
"'
0


‘
211 .
Height Growth Patterns
39
A
130
130
B
39
120
-Nobltllr
33
120
110
-- -- Pacificsliver fir
33
30
110
JO
(}
00[
70
::r
«·
::r
60-
..-
Ž
-
....... ::--:: - ===
::::: - :
----- ------------
12
-
-
-
60
120
100
50
.,
m
140
,
Douglas·flr site Index (SO . y8
39
c
--- Douglas-fir
-
-
-
-- ..... _ -- ' :!
.....
70
-
,A
- = -- ===== == ---,
-...
------_ __ _ _
-
130
39
120
36
1
eo.:.
a
:
30
8
-
10
39
... ............
... ..
.........
..- ..-
.,...,...
12
JO
_
_
10
27
24
60
00
_G
H----I•JoKLMNO1P QRST,--U
Douglas.flr site Index (SO·y8
1V
20
W----X"Yo___
D
130
120
---Not>'elor
110
33
33
30
30
100
27
27
90
§:,.
.c
·ª 21
§:,.
eo
.!2J21
70
19
{!.
-
18
60
15
50
12
40
---PJc•hcsd.erlor
.c
.!
.c
18
15
12
- --
--
10
-----1
60
120
100
80
140
60
-
- --
-4
::
:§
30
---
20
10
120
140
Douglas·fir site Index (SO·Y8
39
E
130
F
120
•20
36
---PJC•'IIoerl•r
33
I
27
80
Douglas·flr site Index (SO. y8
39
- - -------
(}
!!!:
--ooŒGHr,,
110
33
""'
30
-Nobl('f,r
110
)}
30
100
27
90
=
24
(}
80
'a)
21
70
e
-§,
.c
j§
{!.
60
18
15
40
12
- --- -
-----60
.0
100
-
--
-- -
33
-----
.=-== d
15
50
12
40
30
30
20
•o
120
10
24
140
Douglas·lir site Index (50·Y8
60
27
Douglas·lir site Index (SO·yr)
Figure 4. Height by breast-height age and Douglas-fir site index
212
33
100
BO
(King 1966) for: a) noble fir: b) Pacific silver fir; c) Douglas-fir; d)
noble fir and Pacific silver fir: e) Pacific silver fir and Douglas-fir; and
f) noble fir and Douglas-fir.
30
120
140
::r
Harrington and Murray
Table 3. Characteristics of study locations and best annual height growth in true fir stands in western Washington.
Douglas:fir
Location
Soil series
Aspect
I
Melbourne
Melbourne
PACIFIC SILVER FIR
Astoria
Mal
3
4
5
Abiel
NOBLE FIR
6
7
8
9
10
(50 year)
E/e\'{1/ion
Amount
Breast-height age
Meters
Meters
feet
Meters
0
0
125
125
40
40
130
130
1.22
1.22
7,8
1 1. 19,22
N
300
500
700
43
38
37
140
125
120
1. 15
0.95
0. 80
7
8, 17,22
8, 10, 15.26
325
500
825
950
950
43
40
37
26
26
140
130
120
85
85
1.07
1. 15
1.07
0.79
0.82
17
6,7
1 1. 12
12, 15,2 1,3 1
15, 16. 17, 19
GRAND FIR
2
Best a/1111/al height groH·th
site index
N
sw
Boistfort
NE
Boistfort
Sugarloaf
N
s
Katula
Katula
0
0
ated with higher Douglas-fir site indexes. The regression lines
for Pacific silver and noble fir were compared with each other
and with the lines for Douglas-fir (figure 4c) developed from
King (1966).
consistent trend for either high or low elevations to be associ­
ated with deviations from the predicted values.
Aspect, however, did seem to have a greater influence on
height growth of noble and Pacific silver fir than is accounted
When the regression lines for noble and Pacific silver firs for by Douglas-fir site index. For noble fir, south and east as­
were compared (figure 4d), the two species were seen to per­ pects, especially at low to middle elevations, were associated
form similarly on high Douglas-fir sites, but the performance with poorer performance than predicted. For Pacific silver fir,
of Pacific silver fir fell off more sharply than that of noble fir at north aspects were associated with better performance than
the lower site indexes. Predicted height of Pacific silver fir was predicted.
poorer than that of Douglas-fir at all site indexes and for all
ages; the greatest differences were on the poorest sites (figure SUMMARY AND MANAGEMENT
IMPLICATIONS
4e).
The relationship between performance of noble fir and
Height growth of true firs that are free to grow can be char­
Douglas-fir changed over time (figure 4f). Generally our analy­
sis showed that Douglas-fir outperforms noble fir on the higher acterized by a period of slow juvenile growth, an extended pe­
Douglas-fir site indexes; noble fir, however, grows better than riod of rapid growth that is almost linear, and a final phase in
Douglas-fir on the poorer site indexes and its advantage in­ which slower but still appreciable growth continues up to very
creases with age. At breast-height age 13 the regression lines advanced ages. These characteristics mean that juvenile true
cross at site index 23 m (74 ft); by breast-height age 3 3 , the firs often appear at a disadvantage compared with their associ­
regression lines cross at site index 35 m (115 ft). Thus, by ated tree species. Once past the juvenile phase, however, their
breast-height age 33, on sites where Douglas-fir site index is relatively long period of rapid, uniform height growth often
less than 35 m, the predicted height of noble fir is greater than allows the true firs to catch up with or surpass their associates.
that of Douglas-fir. Cumulative height growth of noble fir can
Seasonal height growth takes place during a fairly brief pe­
surpass that of Douglas-fir because the period of maximum riod. Minor height-growth reductions may result if stand en­
height growth in noble fir is longer than that in Douglas-fir;2 tries coincide with the period of rapid terminal expansion.
We found that true firs growing at low to middle elevations
this difference is most pronounced on poorer sites (figure 5 ).
in
western Washington performed better than most foresters
The extended period of good height growth in noble fir allows
it to overtop all its associates eventually--even Douglas-fir on probably would have predicted. Pacific silver fir was fairly
consistently outgrown by both noble fir and Douglas-fir.
good sites.
Douglas-fir site index appears to incorporate the effect of Height growth of Pacific silver fir was quite respectable
elevation for the true firs as well as for Douglas-fir; elevation though, and, with its shade tolerance and fairly narrow crown,
by itself did not appear to account for any additional variation it may warrant greater management consideration--especially
in height growth of noble or Pacific silver firs. There was no as a component of mixed stands. For the same reasons, grand
fir should also be considered. Any species capable of growing
2. Douglas-fir at high elevations have been shown to have slower height
growth at early ages and greater height growth at later ages than trees at low over I 2 m a year should be evaluated seriously. Both grand fir
elevations that have the same height at 100 years (Curtis eta/. 1974). Thus, and noble fir have grown well in experimental plantings on
differences in height-growth patterns of different species may vary with loca­ several sites in Europe (Aldhous and Low 1974; McLean 1980;
.
tion.
2 13
1
Harrington and Murray
Rohrig
1978) and have been recommended for wider use. No­
130
39
120
ble fir tends to have a slower start than Douglas-fir, but the
superior performance of noble fir on poor sites (relative to
Douglas-fir), and its good performance on good sites suggest
110
OQQQNoble!a
-Douqlast,rtK•nb\9661,
0000
30
100
that the species should be considered more frequently for man­
agement on suitable lowland as well as upper-slope locations.
oo:0
Additional research is necessary to predict the productivity of
0
90
80
!!.
70
l
;t
so a
these species under specific site conditions.
50
12
40
30
10
L-----���-77-79-7.11�13�1�5�1�7�19-7.21�23�2�5�2�7��-7.31����·0
Breasl·helghl age (years)
Figure 5. Height growth of three noble fir trees compared with aver­
age height growth of Douglas-fir on Douglas-fir site index 26 m (85ft)
(King 1966).
REFERENCES
Aldhous, J. R .. Low. A. J.
King, James E.
1974. The potential of \\'estem hemlock, westem redcedar, grand
1966. Site index curl'es for Douglas-fir in the Pacific Northwest.
fir m lnoble .fir in Britain. For. Comm. Bull. 49. London. Eng­
Weyerhaeuser For. Pap. 8. Centralia, WA: Weyerhaeuser Co.,
land: Her Majesty's Stationery Office.
For. Res. Cent.
McLean, C.
Cochran, P. H.
1979. Site index and height growth cur\'es for managed, el'en-aged
1980.
stands of ll'hite or grand fir east of the Cascades in Oregon and
1977-78. Scottish For. 34:101-109.
Washington. USDA For Serv. Res. Pap. PNW-252. Portland, OR:
Pac. Northwest For. and Range Exp. Sta.
Curtis. Robert 0 .. Herman, Francis R.. and DeMars, Donald J.
1974. Height growth and site index for Douglas-fir in high-eleva­
tion forests of the Oregon-Washington Cascades. Forest Sci. 20:
307-316.
Abies in Scotland. Report on the Silvicultural Group
Rohrig, E .. ed.
1978. Grundlagenjl'ir den Anbattl'on Abies grandis. [Research on
growing Abies grandis]. Schr. Forst!. Fak. Univ. Gottingen und
Niedersachs. Forst!. Versuchsanst. 54.
Schumacher, Francis X.
1926. Yield, stand, and volume tables for ll'hite fir in the California
·
pine region. Agric. Exp. Sta. Bull. 407. Berkeley, CA: Univ.
Powells, H. A.
1941 . The period of seasonal growth of ponderosa pine and associ­
Calif.
ated species. J. For. 39:601-608.
. compiler.
---
1965. Sill'ics of forest trees of the United States. USDA Agric.
Handb. 271. Washington, D.C.
Hanzlik, Edward J.
1928. Yield, stand, and volume tables for red .fir in California.
Agric. Exp. Stn. Bull. 491. Berkeley, CA: Univ. Calif.
Stage, Albert E.
1959. Site index cun·es for grand fir in the Inland Empire. USDA
1925. A preliminary study of the growth of noble fir.]; Agric. Res.
31(I 0):927-934.
For. Serv. Res. Note 71. Ogden, UT: lntermt. For. and Range Exp.
Sta.
Herman, Francis R.
Williams, Carroll B., Jr.
1967. Growth comparisons of upper-slope conifers in the Cascade
1968a. Seasonal height growth of upper-slope conifers. USDA
Range. Northll'est Sci. 41:51-52.
For. Serv. Res. Pap. PNW-62. Portland, OR: Pac. Northwest For.
---
.Curtis, Robert 0 . and DeMars, Donald J.
.
and Range Exp. Sta.
1978. Height groll'th and site index estimates for noble fir in high­
elel'(ltion forests of the Oregon-Washington Cascades. USDA For.
Serv. Res. Pap. PNW-243.Portland, OR: Pac. Northwest For. and
1968b. Juvenile height growth of four upper-slope conifers in the
Range Exp. Sta.
Serv. Res. Pap. PNW-70. Portland, OR: Pac. Northwest For. and
Washington and northern Oregon Cascade Range. USDA For.
Range Exp. Sta.
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214